Manufacture of cuprous oxide



MANKJFAQIKJRE @F (IUPRUIUS UXEIDE William J. liliarshaw, and Carl .l Harbert, Shaker Heights, Uhio, assignors to The Harshaw Chemlcal Company, Elyria, Ohio, a corporation oi Ohio No El i-awhi e. Application October- M, 19M,

. Serial No. 558,732

4; Claims.

This invention relates to the preparation of cuprous oxide from cupric oxide.

We have discovered that under proper condi I tions cuprlc oxide will react with sulfur accord or rotary retorts. We prefer to use the rotary retort and to create within such retort an atmosphere of steam or of sulfur vapor and sulfurous gases by the use of an excess of sulfur Where ing may be carried out in saggers, crucibles, trays ing to the formula: 5 sulfur is the principal reducing agent or by utilizing a mixture of copper sulfide and sulfur where iCuO+S 2Cu20+SOz copper sulfide is the principal reducing agent. When'a mixture of CuO and sulfur in suitable We may, for e am u he ic l proportions proportions is heated in a non-oxidizing atmos- C110 a CH3 a d t p ly e atom of phere in a temperature range from 50 Q to 10 free sulfur for each two molecules of CuS. When 1000 C., the above indicated reaction takes place the firmg is m Saggers t? a tendency for with the advantage that reduction does not the reaction to be incomplete in the center but a ceed beyond C1120 to the formation of metallic sat'lsfactory product be obtamed in theft copper whereas such reducing agents as carbon If the p f? lsxemoved to.open the and h d 0 e te d to reduc th CuO be d 15 surface will reoiildlze to Cut). This may be pre- 0 y r n t m e e yon vented by exclusion of air until the product is cm to pm me me a 0 copper If cool enough to be stored in closed drums. It may i froporlmons 2 3; 3'' $25 also be allowed to occur if a small proportion of We er 0 emp are or e c P y 1 CuO can be tolerated in the final product. of C110 from 9 to 13 (Preferably 10 w 15) Parts 20 The following table indicates some successful y Weight f Su f r. 10 pa being approximately batch compositions with temperatures and time theoretical according to the above reaction. and the natur of th re ultin product;

Parts Parts by Redu Tempe T Source of CuO in welgh-t of wr f il l Nature of cuprous oxide product weight reducing ofcuo agent agent degrees C. hours 50-50 mix CuO+Gu;0... 50 CuS 15(12) 750 1' Fired in covered crucible Dark surface. Bright red color. Slightly darker red center. Good quality.

50-50 mix CuO-l-CmO 50 CuS 20 (12) 750 to 800 1 Fired in covered crucible. Slightly bluish red color. Conmined some CuSOi. Fair quality. 50-50 mix CUO+CU2O 50 I S 6 (5) 750 to 800 l Fired incovercdsagger. Bluish tint incenteronly. Excellent quality. 50-50 mix CuO+Cuz0 "I 50 S 700 2 Fired in covered crucible. Dark top surface. Bright red underneath. Excellent quality. 5 .50 1; c o+c o "I 501 S 7.5 (5) 750120800 1 Fired in covered crucible. Red color with bluish-red center. Some 011804 present. Fair quality. 50-50 mix CuO+Cu:0 i 50 I S 0 750 1 Fired in covered crucible. Fair quality. CHSOi present.

We may also use copper sulfide instead of sul- The experiments upon which the shove table is fur, the reactionln that case being: based were performed with a, source of copper u 0 O oxide which happened to be most available and 5CuO+Cu 3c +3 2 which contalned approximately C116 and If we use CuS a e reduclng agent We Prefer 50% C1120. We have demonstrated that the CuzO t use for a h 100 parts by weight of (MO from 45 merely acts like an inert material in this reaction 29 to 35 (preferiibly 24 to 3 gi s e f fl and may be neglected except, of course, the fact i g g beng $231 3 Y we 1 a that it must be heated along with thereacting Cor g o e a materials. The color is a very good means for gi g z z ii g g gg zgg gg i gg ggg determining the completeness of the conversion agent; s indicated by the preferred maximum 5 ince CuO is black and CllzO 1S 1bright red (or proportions Stated although that is not absolute yellow if the particle size is smal enough In W necessary In fact we may Operate the process the table we have shown in parentheses 1n the fairly successfully with a. slight deficiency of refourth column the theoretical weight of reducing ducing agent for the formulae stated. The heetagent required for reactions set forth above.

We have experienced some dificulty in respect to eliminating copper sulfate from the product. It is, however, not always necessary to avoid the presence of copper sulfate altogether and, being water soluble, it can be washed out when its presence cannot be tolerated. We do obtain products with as little as 0.2% of copper sulfate.

Having thus described our invention, what we claim is:

1. A process of producing cuprous oxide from cupric oxide which comprises heating a mixture of cupric oxide and a reducing agent of the class consisting of sulfur and copper sulfide and mixtures thereof to a temperature between 650 C. and 1000 C., the proportions being from 9 to 18 parts of reducing agent to 100 parts of CuO by weight in the case of sulfur and from 20 to 35 parts of reducing agent to 100 parts of C'uO by weight in the case of CuS, and proportionally in the case of mixtures, and the heating being carried out in a non-oxidizing atmosphere.

2. A process of producing cuprous oxide from cupric oxide which comprises heating a mixture of cupric oxide and a reducing agent of the class consisting of sulfur and copper sulfide and mixtures'thereof to a temperature between 650 C. and 1000 C., the proportions being from 9 to 18 parts of reducing agent to 100 parts of CuO by weight in the case of sulfur and from 20 to 35 parts of reducing agent to 100 parts of CuO by weight in the case of CuS, and proportionally in the case of mixtures, and the heating being carried out in a non-oxidizing atmosphere and wash aasaors ing the product with water to remove the copper sulfate content therefrom.

3. A process of producing cuprous oxide from cupric oxide which comprises heating a mixture of cupric oxide and a reducing agent or" the class consisting of sulfur and copper sulfide and mixtures thereof to a temperature between 650 C. and 1000 C., the proportions being from 9 to 18 parts of reducing agent to parts of CuO by weight in the case of sulfur and from 20 to 35 parts of reducing agent to 100 parts of CuO by weight in the case of CuS, and proportionally in the case of mixtures, and the heating being car ried out in a rotary retort within which is maintained an atmosphere consisting principally of steam and sulfurous vapors and from which air is largely excluded.

4. A process of producing cuprous oxide from cupric oxide which comprises heating a mixture of cupric oxide and a reducing agent of the class consisting of sulfur and copper sulfide and mixtures thereof to a temperature between 650 C. and 1000 C., the proportions being from 10 to 15 parts of reducing agent to 100 parts of C by weight in the case of sulfur and from 24 to 30 parts of reducing agent to 100 parts of CuO by weight in the case of CuS, and proportionally in the case of mixtures, and the heating being car ried out in a non-oxidizing atmosphere.

WILLIAM J. HARSHAW. CARL J. HARBERT. 

